91820973 has 4 divisors (see below), whose sum is σ = 122427968. Its totient is φ = 61213980.

The previous prime is 91820969. The next prime is 91820987. The reversal of 91820973 is 37902819.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 91820973 - 2² = 91820969 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91820903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15303493 + ... + 15303498.

It is an arithmetic number, because the mean of its divisors is an integer number (30606992).

Almost surely, 2^91820973 is an apocalyptic number.

It is an amenable number.

91820973 is a deficient number, since it is larger than the sum of its proper divisors (30606995).

91820973 is a wasteful number, since it uses less digits than its factorization.

91820973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30606994.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 91820973 is about 9582.3260746021. The cubic root of 91820973 is about 451.1427302617.

The spelling of 91820973 in words is "ninety-one million, eight hundred twenty thousand, nine hundred seventy-three".